POSTRETIREMENT BENEFITS AND EMPLOYEE STOCK OWNERSHIP PLAN - TARGET AND ACTUAL ASSET ALLOCATION (Details)	12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Pension Plan
Target Asset Allocation
Defined Benefit Plan, Target Plan Asset Allocations	100.00%
Actual Asset Allocation
Defined Benefit Plan, Actual Plan Asset Allocations	100.00%	100.00%
Other Retiree Benefits
Target Asset Allocation
Defined Benefit Plan, Target Plan Asset Allocations	100.00%
Actual Asset Allocation
Defined Benefit Plan, Actual Plan Asset Allocations	100.00%	100.00%
Cash and Cash Equivalents | Pension Plan
Target Asset Allocation
Defined Benefit Plan, Target Plan Asset Allocations	2.00%
Actual Asset Allocation
Defined Benefit Plan, Actual Plan Asset Allocations	2.00%	2.00%
Cash and Cash Equivalents | Other Retiree Benefits
Target Asset Allocation
Defined Benefit Plan, Target Plan Asset Allocations	2.00%
Actual Asset Allocation
Defined Benefit Plan, Actual Plan Asset Allocations	2.00%	1.00%
Debt Securities | Pension Plan
Target Asset Allocation
Defined Benefit Plan, Target Plan Asset Allocations	55.00%
Actual Asset Allocation
Defined Benefit Plan, Actual Plan Asset Allocations	55.00%	50.00%
Debt Securities | Other Retiree Benefits
Target Asset Allocation
Defined Benefit Plan, Target Plan Asset Allocations	3.00%
Actual Asset Allocation
Defined Benefit Plan, Actual Plan Asset Allocations	4.00%	5.00%
Equity Securities | Pension Plan
Target Asset Allocation
Defined Benefit Plan, Target Plan Asset Allocations	43.00%
Actual Asset Allocation
Defined Benefit Plan, Actual Plan Asset Allocations	43.00%	48.00%
Equity Securities | Other Retiree Benefits
Target Asset Allocation
Defined Benefit Plan, Target Plan Asset Allocations	95.00%
Actual Asset Allocation
Defined Benefit Plan, Actual Plan Asset Allocations	94.00%	94.00%